Weight of air
Depending on elevation, the air pressure
varies. This is because of the weight of the air that is exerting pressure on
earth. At higher elevation, there is less layer of air that is exerting pressure
so the atmospheric pressure is also less. At lower altitudes or at sea level,
more layer of air is exerting pressure so the atmospheric pressure is also
more. The sun’s energy has nothing to do with air pressure. The energy that the
Earth gets from the sun is more or less constant. The same with density of
nitrogen, and the earth’s magnetic field, they have nothing to do with air
pressure.
Formation of the Earth's Atmosphere. The early Earth was very different from our Earth today. The early Earth experienced frequent impacts from asteroids and meteorites and had much more frequent volcanic eruptions. There was no life on Earth for the first billion years because the atmosphere was not suitable for life.
Yeah hannah is right the answer is c
Answer:

Explanation:
Straight wings are dominant over curved wings
Let Straight wings : H
curved wings : t
smooth eyes are dominant to sparkling eyes
let smooth eyes = H
spark ling eyes = t
tan body is dominant to ebony body color.
Again; Let tan body color be H
Let ebony color be t
If flies that are heterozygous for all three traits are crossed;
we have HtHtHt × HtHtHt
Then the selected trihybrid traits for the cross will be (HHH,HHt, HtH, Htt, tHH, tHt, ttH, ttt)
We will realize that from the punnet square in the diagram below, the proportion of the offspring would you expect to be heterozygous for all three traits (i.e HtHtHt) is asterisk in the punnet square and will be 
= 